The ultimate objective is the measurement of circulatory dynamics in eye disease in order to define disease processes, understand their nature and severity, and suggest appropriate treatment. Televised fluorescein angiography will be used to measure circulatory changes in normal human fundi, pathologic human fundi before and after photocoagulation, and pig fundi before and after photocoagulation. These measurements will be compared with measurements of blood volume flow by radioactive microspheres in pigs. It is hoped that this approach will maximize the quantitative information obtainable from fluorescein angiograms and will thus permit earlier, more precise and new diagnoses in chorioretinopathies. In addition, these studies may elucidate the role of photocoagulation treatment in altering the natural history of these diseases.